Real-Time #AV1 SVC – Unleashing the True Power of #WebRTC

AV1 real-time encoding in standalone webrtc and MilliCast platform was already available since April 2020, as we already covered in previous posts. For those who wanted to use it by themselves in a web app, however, you had to recompile Chrome. While we provided pre-compiled binaries for the community and the happy few brave enough to test it that early, it was a single layer implementation and did not support SVC.

As usage of codec evolves from closed circuits and dedicated lines to be more and more over the public internet, codecs themselves evolves and adopt feature to make media experience over public internet better. A late Annex of H264 (Annex G), SVC has evolved as a mandatory to have feature for any modern codecs. AV1 is the first codec to supports SVC by default. For those interested in more details about how SVC helps, Dr Alex E. wrote a great explanatory blog post back in 2016. Written about VP9, most of the points stay valid for AV1.

For all of last year, the Real-Time Group at AOMEDIA (part of the code group), was hard at work to finish the RTP payload specification which allow for RTP end points to leverage all the codec SVC features, but also for intermediate SFU to be better, stronger and faster. Cosmo Software spearheaded the implementation of all the tests and a reference SFU. The AV1 RTP payload specification is now almost final, tested up to 95%+.

Now is a good time to revisit why AV1 is more important to real-time media beyond just improved compression efficiency. We will also provide details about what to expect in terms of performance.

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